Height adjustable furniture component

ABSTRACT

A height adjustable furniture component has an elongate outer member and an elongate inner member. The outer member has a first end, a second end, and a shoulder at the first end. An inner member is telescopically received in the first end of the outer member to move longitudinally relative to the outer member. The inner member has at least two spaced apart grooves. A locking device in the form of a split ring is configured for selective engagement with the grooves of the inner member and configured such that when engaged with one of the grooves, a portion of the split ring projects from the periphery of the inner member to engage against the shoulder of the outer member to maintain the inner and outer members in their relative longitudinal positions.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

BACKGROUND OF THE INVENTION

1. The Field of the Invention

The invention relates to a height adjustable furniture component. More particularly, but not exclusively, the furniture component may be part of an item of office furniture.

2. The Relevant Technology

A known height adjustable workstation includes a worktop and two or more leg assemblies which form part of a height adjustment mechanism. Each leg assembly has two telescoping leg members, adjustable relative to one another. The height adjustment mechanism includes a handle and drive chain and rotatable parts to effect longitudinal movement of one of the leg members relative to the other leg member. A disadvantage of that type of adjustable workstation is that it has a large number of moving parts, and can therefore be complex and time consuming to assemble.

There are a number of systems with height adjustment mechanisms for securing objects, such as shelves, to posts or legs. Adjustable shelving systems are described in U.S. Pat. No. 4,799,818; U.S. Pat. No. 6,241,108; U.S. Pat. No. 5,881,653; U.S. Pat. No. 6,748,878; and U.S. Pat. No. 5,303,645.

A table leg lock is described in U.S. Pat. No. 5,056,746. The table leg lock has a spring clip carried by a plate for engaging an annular groove in the table leg.

It is an object of at least preferred embodiments of the present invention to provide a height adjustment mechanism for an item of office furniture which addresses the aforementioned disadvantages, and/or which at least provides the public with a useful alternative.

SUMMARY OF THE INVENTION

In accordance with a first aspect of the present invention, there is provided a height adjustable furniture component comprising: an elongate outer member having a first end, a second end, and a shoulder at the first end; an elongate inner member telescopically received in the first end of the outer member to move longitudinally relative to the outer member, the inner member having at least two grooves extending around at least a portion of a periphery of the inner member and which are spaced apart in the elongate direction of the inner member; and a split ring configured for selective engagement with the grooves of the inner member and configured such that when engaged with one of the grooves, a portion of the split ring projects from the periphery of the inner member to engage against the shoulder of the outer member to maintain the inner and outer members in their relative longitudinal positions.

The split ring may be made of a resilient material such that the resilience of the material biases the split ring into engagement with a groove of the inner member.

The split ring may be tapered and the shoulder of the outer member tapered such that an inward force is provided on the split ring by the shoulder of the outer member to force the split ring into engagement with a groove of the inner member. In one embodiment, the split ring comprises a portion which is generally wedge-shaped in cross section and a rib which extends inwardly from the generally wedge-shaped portion, which rib is configured for selective receipt in one of the grooves. The grooves of the inner member are suitably annular grooves, and the rib of the split ring is suitably an annular rib. The cross-sectional shape of the annular rib suitably corresponds substantially to the cross-sectional shape of the grooves. The annular rib and grooves may be substantially semi-circular in cross-section.

In an exemplary embodiment, the split ring has a width and a height, and the width of the split ring is greater than the height of the split ring.

Suitably, the grooves are spaced substantially evenly along the inner member.

The inner and outer members may be elongate tubular members.

The outer member may comprise a joining sleeve configured for attachment to a member to provide support to the furniture component, and the shoulder may be part of the joining sleeve.

The outer member may comprise a bush which provides a bearing surface against which the inner member can slide, and the shoulder may be part of the bush.

The grooves of the inner member may be annular grooves.

In accordance with a second aspect of the present invention, there is provided a height adjustable workstation comprising a worktop and one or more height adjustable furniture components as outlined in the first aspect above configured to support the worktop from a floor surface.

In accordance with a third aspect of the present invention, there is provided a height adjustable chair arm comprising a height adjustable component as outlined in the first aspect above, wherein one of the inner and outer members is connected to a part of the chair, and the other of the inner and outer members supports an arm rest.

In accordance with a fourth aspect of the present invention, there is provided a height adjustable furniture component comprising: an elongate outer member having a first end, a second end, and a tapered shoulder at the first end; an elongate inner member telescopically received in the first end of the outer member to move longitudinally relative to the outer member, the inner member having at least two spaced apart annular grooves; and a split ring configured for selective engagement with the annular grooves of the inner member and configured such that when engaged with one of the grooves, a tapered surface of the split ring projects from the periphery of the inner member to engage against the tapered shoulder of the outer member which biases the split ring inwardly against the inner member and maintains the inner and outer members in their relative longitudinal positions.

The invention consists in the foregoing and also envisages constructions of which the following gives examples only.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described by way of example and with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of a workstation with leg assemblies each of which is a preferred embodiment height adjustable component;

FIG. 2 is an exploded underside perspective view of the workstation of FIG. 1;

FIG. 3 is an exploded perspective view of a leg assembly of the workstation of FIG. 1, which leg assembly is a preferred embodiment of the height adjustable furniture component;

FIG. 4 is a perspective view of an inner leg member and mounting plate of the leg assembly of FIG. 3;

FIG. 5 is a front view of the leg assembly of FIG. 3;

FIG. 6 is a side view of the leg assembly of FIG. 3;

FIG. 7 is a cross section through line 7-7 of FIG. 6;

FIG. 8 is a close up view of detail A of FIG. 7 showing the split ring engaged between the annular groove of the inner member and the tapered shoulder of the outer leg member;

FIG. 9 is a plan view of a preferred embodiment split ring from the leg assembly of FIG. 3;

FIG. 10 is a side view of the split ring of FIG. 9;

FIG. 11 is a cross section through line 11-11 of FIG. 10;

FIG. 12 is a close up view of detail B of FIG. 11;

FIG. 13 in a plan view of a bush from the outer leg member of the leg assembly of FIG. 3, which provides a bearing surface for the inner leg member;

FIG. 14 is a front view of the bush of FIG. 13;

FIG. 15 is a side view of the bush of FIG. 13;

FIG. 16 is a cross section through line 16-16 of FIG. 13;

FIG. 17 is a close up view of detail C of FIG. 16; and

FIG. 18 is an exploded perspective view of a height adjustable chair arm in accordance with an alternative preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1 and 2, a preferred embodiment workstation 1 for use in an office environment has a work surface 3, a pair of adjustable side leg assemblies 5, an adjustable central leg assembly 7, and chassis rail assemblies 9 which extend between each one of the side leg assemblies 5 and the central leg assembly 7.

Each adjustable leg assembly 5, 7 is a preferred embodiment height adjustable component, and has an elongate outer leg member 11 and an elongate inner leg member 13 which is telescopically received in a first end of the outer leg member 11 to move longitudinally relative to the outer leg member 11. The lower end of the inner leg member 13 is received in the outer leg member. Sliding of the inner leg member 13 in the outer leg member 11, allows the overall length of the leg assembly, and consequently the height of the workstation 1, to be adjusted. As will be described in more detail with reference to FIG. 3, a locking member in the form of a split ring 15 maintains the relative longitudinal positions of the inner and outer leg members.

The upper end of the inner leg member 13 is connected to or integral with a mounting plate 17, as shown in FIG. 4. The mounting plate 17 is adapted for attachment to the underside 19 of the work surface 3 of the workstation using fasteners such as screws 21 or the like.

The outer leg member 11 preferably comprises a body 11 a, which is generally cylindrical. In the form shown, the body 11 a is substantially circular in cross section, although it will be appreciated that other cross sections could be provided. In the form shown, the inner leg member 13 is also substantially circular in cross section, but again could be a different cross section. Preferably, the body of the inner member and the outer member comprise metal cylindrical tubes, but other forms and materials could be used.

In the form shown, a joining sleeve 23 which incorporates an engagement portion 23 a including a threaded boss 23 b for connecting to a respective chassis rail assembly 9, is connected to the body 11 a of the outer leg member. The joining sleeve 23 is preferably a cast component, and may have a lower part 23 c which is press-fit into the body 11 a of the outer leg member 11. The joining sleeve 23 of each side leg assembly 5 comprises a single engagement portion 23 a for connecting to one end of a chassis rail assembly 9. The joining sleeve 23 of the central leg assembly 7 has two engagement portions for connecting to the opposite ends of the chassis rails 9.

The individual chassis rails 9 a, 9 b in each chassis rail assembly 9 are held in a spaced apart configuration by end spacer plates 9 c, which are configured to engage with the engagement portions 23 a of the joining sleeves 23. The end spacer plates-9 c are connected to the bosses 23 b in the engagement portions 23 a of the joining sleeves 23 by fasteners such as Allen bolts 25 or the like. The chassis rail assemblies provide additional stability to the workstation assembly. In the embodiment shown, the chassis rail assemblies 9 are angled at approximately 120° to each other to correspond generally to the shape of the worktop 3 of the workstation. It will be appreciated that other configurations could be used—for example a generally straight chassis rail could be provided between the legs in a workstation having only a pair of legs. Alternatively, the chassis rails could be curved.

Bushes 25 are preferably clipped into the upper and lower ends of each joining sleeve 23, to provide bearing surfaces against which the inner leg members 13 telescopically slide. As can be seen in FIGS. 13 to 17, each bush 25 has a portion 25 a with an external frustoconical shape. That is configured for receipt in corresponding tapered apertures in the upper and lower ends of the joining sleeve 23. A radially outwardly extending flange 25 b is provided at one end of the bush to engage against a respective shoulder in the joining sleeve 23. The bushes are made of a suitable material such as nylon or other plastic for example, and provide low friction bearing surfaces within the joining sleeve 23 against which the inner leg member slides.

At least the upper bush of each leg assembly also includes an internal tapered surface 25 c which forms a shoulder against which the split ring engages.

An outwardly-facing projection 25 d on each bush 25 is configured to engage in a respective aperture 23 d of the joining sleeve to connect those components together.

Each side leg assembly 5 has a supporting foot 27 connected to the outer leg member 11 at a second end of the outer leg member by a fastener such as a bolt 29 and a washer 31. The threaded end of the fastener 29 is threaded into a nut 11 c which is fixed relative to the outer leg member 11 a by a plate 11 b. The plate 11 b, nut 11 c, and associated washer 11 d are shown in FIG. 7. A spacer component 33 is received in the base of the outer leg member 11, to enhance the stability of the leg under load. The feet 27 of the side leg assemblies 5 are preferably generally elongate and cantilevered off the base of the outer leg members 11 to provide additional stability to the worktop assembly. As shown in FIG. 2, the underside of each foot 27 has two gliders 27 a made of a suitable material such as plastic. The gliders are preferably adjustable relative to the foot to provide some fine height adjustment of the foot. Preferably, the gliders are threaded to the main part of the foot. The central leg assembly 7 has an adjustable foot 35, which may again screw into a nut 11 c in the outer member 11 of the central leg assembly.

As shown in FIGS. 3 and 4, the inner leg member 13 has a plurality of grooves 39 which extend around at least a portion of the periphery of the inner leg member 13 and which are spaced apart in the elongate direction of the inner leg member. In the embodiment shown, the grooves are annular grooves 39 provided along at least part of the length of the inner member. The inner leg member preferably also includes indicia such as numbers, letters, or the like printed or cast between the grooves which indicate the adjusted position of the leg members and thereby the height of the workstation top. That is useful if the height of more than one component is being adjusted, to enable a user to easily determine whether they have been adjusted to the same amount. The annular grooves 39 are configured to be engaged by the split ring 15 which is shown in detail in FIGS. 9 to 12 for securing the inner and outer leg members in their relative longitudinal positions. In the embodiment shown, the grooves 39 are substantially evenly spaced along the inner leg member 13. Preferably, the annular grooves 39 have a semi circular cross section.

Each leg assembly has a locking device in the form of a split ring 15. The split ring 15, as shown in FIGS. 9-12, is configured for selective engagement with one of the annular grooves 39 in the inner member 13. The split ring is an annular component which preferably comprises a single member which has an exterior surface 15 a that is tapered outwardly towards its upper edge and is thickest at its top portion. The taper on the outer surface of the split ring may be about 15° to 45° to vertical. Preferably the taper on the outer surface of the split ring is about 30° to vertical. A split 15 b is provided in the split ring. As can be seen in FIG. 12, in cross section the split ring has a generally wedge-shaped portion 15 c with an inwardly-directed annular rib 15 d formed on its interior surface which can be selectively engaged in the grooves 39. Preferably, the rib 15 d has a semicircular cross section to correspond to the cross section of the grooves.

The split ring 15 preferably has a width or diameter W significantly greater in size than its depth D. In the embodiment shown, the split ring has an outer diameter in the order of thirteen to fourteen times its depth, although it will be appreciated that other variants could be provided. Preferably, the ratio of the width to depth is greater than about 10:1. By providing a split ring that is significantly wider than its depth, a large diameter is provided to support the load through the leg assembly, while enabling a large number of adjustment positions to be provided.

The split ring 15 is further configured such that when engaged with the groove 39, a portion of the split ring, and in the embodiment shown the wedge-shaped portion 15 c including the tapered outer surface 15 a projects from the periphery of the inner leg member 13 beyond the groove 39 to engage against a shoulder 25 c of the outer leg member 11 to maintain the inner and outer legs in their relative longitudinal positions. FIG. 8 shows the split ring engaged with the groove 39 and against the shoulder 25 c. The corresponding internal surface of the shoulder 25 c of the outer leg member 11 is tapered to correspond substantially to the taper of the outer surface of the split ring. As such, the taper on shoulder 25 c of the outer leg member may be about 15° to 45° to vertical. Preferably the taper on the shoulder 25 c of the outer leg member 11 is about 30° to vertical. The interaction of the tapered surfaces provides a locking bias on the split ring 15 inwardly on the groove 39 of the inner leg member.

The split 15 b allows the ring to be placed onto the inner leg member 13. The split also allows the ring to reduce in diameter as a force is applied on the ring by the shoulder of the outer leg member 11. The split ring is preferably self-biased inwardly a sufficient amount to engage the groove 39 to at least some extent even in the absence of external force from the outer leg member 11. That self-biasing is suitably a result of the resilience of the material used to make the split ring.

The split ring 15 may be molded from a suitable plastic material or formed from a suitable non-plastic metal such as spring steel. The preferred split ring is made of acetal.

The leg assembly is assembled by placing the split ring 15 around the inner leg member 13 so that split ring is loosely received in a groove 39 at the desired height. The inner leg member 13 is placed inside the outer leg member 11. The weight of the work surface 3 urges the inner leg member 13 downwards within the outer leg member 11. The tapered surfaces of the split ring 15 and the shoulder 25 c produce a wedging action which causes the split ring to be radially compressed. The rib 15 d on the split ring securely engages with the groove 39 to secure the inner and outer leg members in their longitudinal positions.

To adjust the height of the leg assembly, the inner leg member 13 is lifted a small amount, the split ring 15 is pulled open to clear the groove 39, is moved to another groove 39, is released to engage that other groove 39, and the inner leg member 13 is moved downwardly relative to the outer leg member 11 such that the shoulder of the outer leg member 11 engages against the split ring 15.

Rather than being a leg assembly of a workstation, the preferred embodiment height adjustable furniture component could be used in a different type of furniture. For example, the furniture component could be a height adjustable chair arm for an office chair. One of the inner and outer members could be connected to part of the chair such as a main transom of the chair for example, and the other of the inner and outer members could be connected to an arm rest. Such an arrangement is shown in FIG. 18. Unless described below, the features and operation should be considered the same as for FIGS. 1 to 17, and like reference numerals are used to indicate like parts with the addition of 100.

The height adjustable chair arm 101 for an office chair has an outer member 111 and an inner member 113 which is telescopically received in the outer member 111. A mounting portion 112 extends generally transversely from the outer member 111, and is configured to mount the arm support to part of the chair, such as the main transom (not shown) of the chair. In the embodiment shown, the mounting portion 112 includes a support portion 112 a which defines a shoulder which abuts against the main transom, and an engagement portion 112 b which engages in an aperture or channel in the main transom. It will be appreciated that the chair will generally be provided with two such chair arms, one on either side of the chair. Rather than engaging with the main transom, the chair arm could engage with a different part of the chair.

An arm rest 114 is carried by the inner member 113. Preferably, the arm rest comprises a cushioned pad to comfortably support a chair occupant's arm. In a preferred embodiment, the arm rest 114 is movable relative to the inner member 113, and an actuator 114 a is provided to release a locking mechanism to enable said movement.

The inner member 113 again has a number of spaced apart grooves which extend around at least a portion of the periphery of the inner member. The grooves are preferably annular grooves as shown. A split ring 115 is configured to be selectively engaged with any of the grooves. The upper edge of the outer member 111 will again preferably be provided with a tapered shoulder, such that when the split ring is engaged with one of the grooves and the shoulder of the outer member engages with the tapered outer surface of the split ring, the split ring is radially compressed against the groove of the inner member.

The height of the arm rest can be adjusted by lifting the arm rest slightly, releasing the split ring from the groove, moving the split ring to another groove, and releasing the arm rest so that the outer member engages against the split ring. Bushes or the like may again be provided within the outer member if desired.

Preferred embodiments of the invention have been described by way of example only and modifications may be made thereto without departing from the scope of the following claims.

For example, the adjustable leg assemblies are described as having the inner member 13 forming the top portion of the leg assembly and the outer member 11 forming the lower portion. It will be understood that the arrangement could be inverted so that the upper portion is the outer member 11 and the lower portion is the inner member 13. Similarly, some of the components of the arm support could be inverted such that the outer member is the upper member which supports the arm rest and the inner member is the lower member which connects to part of the chair.

The worktop is shaped with two portions at an angle to each other with three adjustable leg assemblies, as shown in FIGS. 1 and 2. However, the leg assemblies may be used with other shapes of worktop and more or fewer adjustable leg assemblies may be used. For example, the workstation may have a conventional rectangular shaped work top and two adjustable leg assemblies.

The inner members 13, 113 are described as having evenly spaced annular grooves. The spacing between the grooves 39, 139 may be decreased or increased to provide greater or finer height adjustment.

The split ring 15 is described as having a semicircular rib on its interior surface. However, the rib may have any other profile such as square. It will be understood that the annular grooves 39 of the inner member 13 would generally have a corresponding shaped profile. In an alternative embodiment, the split ring could be provided without the rib. Rather, a portion of the wedge-shaped body of the split ring could be received in the annular groove of the inner member. However, it is preferred that a rib is provided, as it is easier to remove the split ring from engagement with the groove.

In the embodiment shown, the tapered shoulder 25 c of the outer member against which the tapered outer surface of the split ring engages is part of the bush 25. Alternatively, the bushes could be dispensed with and the tapered shoulder could instead be provided as part of the joining sleeve 23. In embodiments which do not use chassis rail assemblies, the joining sleeve 23 could also be dispensed with and the tapered shoulder could be part of the main body 11 a of the outer member. Alternatively, the bush 25 could be configured to engage directly into the main body 11 a, and the tapered shoulder could be provided in the bush.

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. 

1. A height adjustable furniture component comprising: an elongate outer member having a first end, a second end, and a shoulder at the first end; an elongate inner member telescopically received in the first end of the outer member to move longitudinally relative to the outer member, the inner member having at least two grooves extending around at least a portion of a periphery of the inner member and which are spaced apart in the elongate direction of the inner member; and a split ring configured for selective engagement with the grooves of the inner member and configured such that when engaged with one of the grooves, a portion of the split ring projects from the periphery of the inner member to engage against the shoulder of the outer member to maintain the inner and outer members in their relative longitudinal positions.
 2. A height adjustable furniture component as claimed in claim 1, wherein the split ring is made of a resilient material such that the resilience of the material biases the split ring into engagement with a groove of the inner member.
 3. A height adjustable furniture component as claimed in claim 1, wherein the split ring is tapered and the shoulder of the outer member is tapered such that an inward force is provided on the split ring by the shoulder of the outer member to force the split ring into engagement with a groove of the inner member.
 4. A height adjustable furniture component as claimed in claim 3, wherein the split ring comprises a portion which is generally wedge-shaped in cross section and a rib which extends inwardly from the generally wedge-shaped portion, which rib is configured for selective receipt in one of the grooves.
 5. A height adjustable furniture component as claimed in claim 4, wherein the grooves of the inner member are annular grooves, and the wherein the rib of the split ring is an annular rib.
 6. A height adjustable furniture component as claimed in claim 4, wherein the cross-sectional shape of the rib corresponds substantially to the cross-sectional shape of the grooves.
 7. A height adjustable furniture component as claimed in claim 6, wherein the rib and grooves are substantially semi-circular in cross-section.
 8. A height adjustable furniture component as claimed in claim 1, wherein the split ring has a width and a height, and wherein the width of the split ring is greater than the height of the split ring.
 9. A height adjustable furniture component as claimed in claim 1, wherein the grooves are spaced substantially evenly along the inner member.
 10. A height adjustable furniture component as claimed in claim 1, wherein the inner and outer members are elongate tubular members.
 11. A height adjustable furniture component as claimed in claim 1, wherein the outer member comprises a joining sleeve configured for attachment to a member to provide support to the furniture component, and the shoulder is part of the joining sleeve.
 12. A height adjustable furniture component as claimed in claim 1, wherein the outer member comprises a bush which provides a bearing surface against which the inner member can slide, and the shoulder is part of the bush.
 13. A height adjustable chair arm as claimed in claim 1, wherein the grooves of the inner member are annular grooves.
 14. A height adjustable workstation comprising a worktop and one or more height adjustable components as claimed in claim
 1. 15. A height adjustable chair arm comprising a height adjustable component as claimed in claim 1, wherein one of the inner and outer members is connected to a part of the chair, and the other of the inner and outer members supports an armrest.
 16. A height adjustable furniture component comprising: an elongate outer member having a first end, a second end, and a tapered shoulder at the first end; an elongate inner member telescopically received in the first end of the outer member to move longitudinally relative to the outer member, the inner member having at least two spaced apart annular grooves; and a split ring configured for selective engagement with the annular grooves of the inner member and configured such that when engaged with one of the grooves, a tapered surface of the split ring projects from the periphery of the inner member to engage against the tapered shoulder of the outer member which biases the split ring inwardly against the inner member and maintains the inner and outer members in their relative longitudinal positions. 